British star Jude Law is to become a dad for the fourth time – although his ‘baby-mama’ is being kept a secret.

The 36-year-old Alfie and Cold Mountain star has confirmed the pregnancy but is staying tight-lipped about the woman’s identity.

The famous father-of-three has vowed to fully support his new off-spring who was the result of a Christmas fling.

“Jude Law can confirm that following a relationship last year he has been advised that he is to be father of a child due in the fall of this year,” his spokesman said.

“Mr Law is no longer in a relationship with the individual concerned but he intends to be a fully supportive part of the child’s life.

This is an entirely private matter and no other statements will be made.”

Now the Hollywood rumor-mill is set to go into overdrive as to the woman’s identity with the star being linked to model Lily Cole, journalist Kim Hersov, German underwear model Susan Hoecke and socialite Kimberley Stewart.

The affair reportedly happened when he was working on the set of his new movie Sherlock Holmes in New York over Christmas.

The actor is currently starring in the title role in a West End production of Hamlet in London which will switch to Broadway in autumn.

Law has three children with former wife Sadie Frost: Rafferty, 12, Iris, 8, and Rudy, 6.

He was previously engaged to Sienna Miller in November 2005 but is currently single.